HID: logitech: don't use stack based dj_report structures

On a system with a logitech wireless keyboard/mouse and DMA-API debugging
enabled, this warning appears at boot:

kernel: WARNING: at lib/dma-debug.c:929 check_for_stack.part.12+0x70/0xa7()
kernel: Hardware name: MS-7593
kernel: uhci_hcd 0000:00:1d.1: DMA-API: device driver maps memory fromstack [addr=ffff8801b0079c29]

Make logi_dj_recv_query_paired_devices and logi_dj_recv_switch_to_dj_mode
use a structure allocated with kzalloc rather than a stack based one.
Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-logitech-dj.c

@@ -436,27 +436,37 @@ static int logi_dj_recv_send_report(struct dj_receiver_dev *djrcv_dev,
 
 static int logi_dj_recv_query_paired_devices(struct dj_receiver_dev *djrcv_dev)
 {
-	struct dj_report dj_report;
+	struct dj_report *dj_report;
+	int retval;
 
-	memset(&dj_report, 0, sizeof(dj_report));
-	dj_report.report_id = REPORT_ID_DJ_SHORT;
-	dj_report.device_index = 0xFF;
-	dj_report.report_type = REPORT_TYPE_CMD_GET_PAIRED_DEVICES;
-	return logi_dj_recv_send_report(djrcv_dev, &dj_report);
+	dj_report = kzalloc(sizeof(dj_report), GFP_KERNEL);
+	if (!dj_report)
+		return -ENOMEM;
+	dj_report->report_id = REPORT_ID_DJ_SHORT;
+	dj_report->device_index = 0xFF;
+	dj_report->report_type = REPORT_TYPE_CMD_GET_PAIRED_DEVICES;
+	retval = logi_dj_recv_send_report(djrcv_dev, dj_report);
+	kfree(dj_report);
+	return retval;
 }
 
 static int logi_dj_recv_switch_to_dj_mode(struct dj_receiver_dev *djrcv_dev,
 					  unsigned timeout)
 {
-	struct dj_report dj_report;
+	struct dj_report *dj_report;
+	int retval;
 
-	memset(&dj_report, 0, sizeof(dj_report));
-	dj_report.report_id = REPORT_ID_DJ_SHORT;
-	dj_report.device_index = 0xFF;
-	dj_report.report_type = REPORT_TYPE_CMD_SWITCH;
-	dj_report.report_params[CMD_SWITCH_PARAM_DEVBITFIELD] = 0x3F;
-	dj_report.report_params[CMD_SWITCH_PARAM_TIMEOUT_SECONDS] = (u8)timeout;
-	return logi_dj_recv_send_report(djrcv_dev, &dj_report);
+	dj_report = kzalloc(sizeof(dj_report), GFP_KERNEL);
+	if (!dj_report)
+		return -ENOMEM;
+	dj_report->report_id = REPORT_ID_DJ_SHORT;
+	dj_report->device_index = 0xFF;
+	dj_report->report_type = REPORT_TYPE_CMD_SWITCH;
+	dj_report->report_params[CMD_SWITCH_PARAM_DEVBITFIELD] = 0x3F;
+	dj_report->report_params[CMD_SWITCH_PARAM_TIMEOUT_SECONDS] = (u8)timeout;
+	retval = logi_dj_recv_send_report(djrcv_dev, dj_report);
+	kfree(dj_report);
+	return retval;
 }